Is PBL better than traditional curriculum?

Since the problem based learning (PBL) curriculum was first introduced at McMaster medical school in the late 1960s it has been widely recognised as a progressive learner­centred active learning approach and currently underpins the philosophy of the entire medical curriculum in over 10% of medical schools worldwide.1 In the United Kingdom medical schools in Manchester, Glasgow, and Liverpool have already adopted the PBL curriculum as recommended by the General Medical Council,2 and several other schools have partially done so or are planning to do so.

But what is PBL? Although many medical teachers hold strong views on what counts as PBL, there is no universal definition.3 Typically, students working in small groups are given written real life problems. From these problems the students identify phenomena which require explanations, agree on learning objectives, research individually on identified issues, report back, and apply newly acquired information to the problem.4 The term PBL is often used to describe a curriculum based entirely on the problem based philosophy—that is, the PBL curriculum—but it has also been used to describe any educational method with problem solving as a component. It is implemented differently at different schools. There is therefore a conceptual fog about PBL and “problem first learning” may be a better term for this approach. 3 Is there evidence that PBL is more effective than traditional approaches? Until recently, two meta­ analyses of studies on the outcomes of PBL between the 1970s and 1992 gave considerable encouragement. One showed significant improvement on clinical performance, students' programme evaluation, and measures of humanism5; the other showed better clinical examination skills and faculty evaluation but worse basic science examination scores for PBL.6 First and second year students on the new PBL curriculum at Liverpool medical school seemed to be more satisfied with their course compared with previous students, although they were more likely to feel unclear about the course objectives and the standard of work required.7 Third year students at Manchester also seemed to be generally positive with the integrated problem based learning curriculum in a clinical environment.8 As yet, there has been no research comparing graduates of PBL with traditional curriculums.

Such optimism was shattered by a more recent meta­analysis which included studies published between 1992 and 1998.9 It revealed no convincing evidence that PBL improves knowledge base and clinical performance, at least not of the degree expected from the resources required for a PBL curriculum. In response to these findings, some people defended PBL by arguing that it is unreasonable to expect students to do significantly better in a PBL than a traditional curriculum, as students are groomed and selected for success in a traditional curriculum leading up to medi­ cal school. 10 Other people argued that PBL was not a single intervention and that in real environments many complex factors could have obscured any genuine effects of PBL.11 Even if valid, these arguments alone do not justify the efforts and resources required to change from a traditional curriculum to a PBL one. Therefore, advocates of PBL shift their emphasis from PBL outcomes to processes. They claim that PBL provides a more challenging, motivating, and enjoyable approach to education11 as well as enhancing the work environment for students and staff. 10 Although there is an abundance of reports of favourable learning experience from a PBL curriculum (see box), they do not allow definitive comparisons to be made between PBL and traditional curriculums for several reasons.

Firstly, medical schools which opted to change to a new PBL curriculum might be staffed by more enthusiastic teachers and had more resources. Secondly, students with more independent learning styles might be more inclined to choose medical schools with a PBL curriculum. Thirdly, in spite of a wealth of theories on how the PBL process could be educational, there has been little qualitative research on how PBL works in practice. So should the PBL curriculum be implemented more widely? Several issues should be considered.

Firstly, PBL is not an all or nothing phenomenon. Several successful medical schools—for example, Dundee and Newcastle—incorporate elements of PBL into their teaching. Secondly, the potential benefits of implementing a PBL curriculum should be compared with those where the same resources, staff time, and training is spent on improving the current curriculum. Thirdly, curriculums based on group PBL might not allow students to address their individual learning needs and to learn at a pace different from the group.12 Finally, the learning styles of some students might suit one type of curriculum better than the other, and the exclusive use of one approach may disadvantage some students. The jury is still out, and more research on the PBL process is needed.

Wai­Ching Leung, lecturer in public health medicine, University of East Anglia
Email: w­c.leung@uea.ac.uk


studentBMJ 2001;09:305-356 September ISSN 0966-6494

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